The most senior US aid and military delegation to visit Burma in years left Rangoon empty-handed yesterday after the regime refused to give any firm commitment about accepting increased aid for the victims of the cyclone disaster.

The team that accompanied the first US flight loaded with emergency supplies met cabinet ministers from the ruling junta to offer relief, disaster management expertise and a muscular military capability to deliver aid to the hardest hit areas. But the Burmese delegation merely said it would consider the offer, even as aid agencies warned that only 10% of the logistical staff needed to cope with the estimated 1.9 million homeless had arrived in the country 10 days after Cyclone Nargis struck.

Few now believe the isolated Burmese leadership is likely to have a change of heart over large scale outside assistance, despite international pressure and mounting anger of the UN and aid agencies.

Further consignments of aid - including the US flight - entered Burma yesterday, but there were continued warnings that it was far from enough to meet the scale of the disaster, which is believed to have killed more than 100,000 people.

State television raised the official death toll to 31,938, with 29,770 missing.

The UN's World Food Programme said it was delivering emergency rations to those in the hardest hit region, the Irrawaddy delta, at only a fraction of that required. "We think we need to be moving 375 tonnes of food a day down into the affected areas," said Marcus Prior, a WFP spokesman in Bangkok. "We are doing less than 20% of that."

But Andrew Kirkwood, the country director of Save the Children, saw a glimmer of hope, estimating that as many as half of those affected by the cyclone had been reached, a big rise from the dismal proportion of 10% late last week.

However, there was little sign of progress for international disaster experts awaiting visas to assist with the rescue effort. The UN senior representative in Burma flew to the capital, Naypyidaw, and presented the generals with a list of 60 "critical" UN and agency staff.

The US's first shipment, of 12 tonnes of mosquito nets, blankets and water, was dispatched from a Thai air force base after days of negotiations with the Burmese. Pallets of relief adorned with banners proclaiming "USaid from the American people" were slid aboard the C-130 military transport, with speeches by Admiral Timothy Keating, head of US Pacific Command, and Henrietta Fore, US Agency for International Development (USaid) administrator.

"This is Burma's hour of need, and the need is urgent," said Fore, before boarding with the team bound for Rangoon. "We stand ready to help with our humanitarian relief items."

The US determination to have its own personnel oversee the distribution of its aid supplies rather than "dump" them at Rangoon airport appeared to have evaporated yesterday even as a senior USaid official continued to insist it was vital.

"Basically, in order to rapidly and dramatically increase the scale of the supplies you need expert assessment teams on the ground," said Olivier Carduner, USaid's Asia development director. "No one wants to see large amounts of relief supplies on the ground when they're not being used."

Initial talks that would have allowed Save the Children to take control of the US consignment faltered when the regime said it would take charge. A Burmese government spokesman, Ye Htut, said later that the US aid had been transferred to military trucks and was due to be ferried by helicopter to the delta within hours.

The US team offered the Burmese delegation a further £7.5m in food aid and logistical assistance, an increase from the £1.6m it has already committed. The fresh donation would include 1,000 tonnes of emergency food over the coming weeks.

The delegation added that six C-130 aircraft, numerous helicopters and 4,000 marines were on standby to help if permission was given. Three US navy ships will be stationed in international waters off the Irrawaddy coastline within 48 hours, Keating said on his return. But he said the Burmese would only take the various offers of assistance "under consideration".

Fore said: "We'll take it one day at a time. I believe our discussions were a good first step. I see it as a good beginning, but it will take time."